This invention relates to method and apparatus for assembling a transformer core based on inserting a lamination of rectangular plates formed of a magnetic material (e.g., silicon steel plates or amorphous magnetic alloy bands) in spaces defined in transformer coils formed of windings of primary and secondary coils, and bringing the opposite ends of the magnetic material lamination into abutment with each other to form the lamination into an annular shape.
A transformer core assembly technique such as the one disclosed in Japanese Patent Unexamined Publication No. 63-241911 is known.
FIG. 5 shows a state in which laminated core 1 is inserted in coils 2a and 2b. The core 1 is formed into an annular shape as shown in FIG. 6.
FIG. 7 shows an enlarged cross section of a portion VII shown in FIG. 6. The smaller the gap G between abutting opposite end portions 1l and 1r of the laminated magnetic material, plates of the core 1 are, more improved the crossing of lines of magnetic force over the connected portions is, so that the performance of the transformer is improved.
FIG. 8 shows in an enlarged scale the details of the opposite end portions of laminated magnetic material plates constituting the core 1 in its manufacturing step shown in FIG. 5.
The above-described well-known technique had a problem of occurrence of large gaps between abutting portions of laminated plates with a resultant increase in the resistance to the magnetic circuit because the abutment-lamination assembly step which influences the core performance was conducted by a manual operation. Further, a core formed of an amorphous magnetic alloy had a drawback that the material becomes brittle during a pretreatment step, i.e., core annealing step, so that the core tends to crack or break to deteriorate its characteristics. There are further problems in the manual assembling operation; two operators are required for the assembling operation because the core and the coils are heavy, and the operation speed is reduced in order to avoid deteriorations in the characteristics pointed out above, resulting in an increase in the assembly cost.